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In the age of constant scientific advancements, the topic of gene editing has become increasingly popular. Gene editing (additionally known as genome editing and genetic engineering) is a kind of engineering in which DNA is modified, deleted, inserted, or replaced in the genome of a living organism. The most widely acknowledged technique is called CRISPR-Cas9, a method that can change any section or sequence of DNA with accuracy and precision. CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats”, which is a shorthand for CRISPR-Cas9. Cas-9 is an enzyme that functions as a pair of molecular scissors that can adjust DNA. 

While CRISPR has been a functioning technique for just under a decade, it has been around longer than this century. Scientists have been investigating the presence of CRISPR in bacteria since the 1980s. The first report on CRISPR was officially published in 1987 by a group of Japanese scientists. While studying a gene that controls protein-encoding in Ecoli, the research group discovered repeating palindromic DNA sequences separated by a spacer of DNA sequences. Over the next few years of research, scientists found that the previously noted repeating sequences were present in a variety of bacteria and single-cell organisms.

Breaking down what CRISPR does is essential in understanding gene editing. In the simplest term, CRISPR is like the copy and paste function on a computer. When bacteria encounter a foreign invasive agent, they can incorporate copies of the foreign invasive agent into their genome as spacers between the sequences and spacers in the original DNA. 

The new spacers then improve the bacteria’s immune response by providing an organized sequence for RNA molecules to target the same DNA sequence in future invasive agents. When the RNA molecules recognize a familiar incoming agent, it guides CRISPR to that sequence. Then the Cas enzymes come in. Cas cuts up the DNA structure then allows the cell to attempt a repair operation of the DNA, which generally causes a mutation. 

In 2012, a group of researchers from UC Berkley announced that they discovered a way to hijack the CRISPR immune function to create a new gene-editing process. Thus, CRISPR-Cas9 was created. The researchers created a Cas9 enzyme that paired with hybrid RNA that could be programmed to cut, replace, and identify any section of the gene sequence. 

With CRISPR-Cas9 introduced onto the scene, scientists are able to:

  • Add a new gene.
  • Delete a gene.
  • Activate dead genes.
  • Control the activity level of a gene.

Although CRISPR contains a high amount of potential, the risk factor is also high. The ability to edit genes also invites the possibility to misuse it. Gene editing has the potential for both positive and negative uses. Before we can evaluate the future methods, we first need to understand what CRISPR-Cas9 has to offer. The future of genome editing is here, and the next question lies in what we will do with the possibilities we now have.